Selective messaging systems, such as paging or data systems, are known. Many of these systems are simulcast systems where a message is simultaneously or nearly simultaneously launched from each or all transmitters in a system. Practitioners have found these systems provide excellent coverage in that a messaging unit, such as a pager, is very likely to receive any message intended for the unit, regardless of the location of the unit or lack of knowledge on the part of the system of the location of the unit. However such systems have poor if any reuse capability as all transmitters are transmitting or attempting to deliver the same message at the same time.
Other systems are arranged to practice targeted message delivery. In these instances only a transmitter(s) likely to reach the messaging unit is(are) used to transmit or deliver a message to the unit. Reuse is improved as transmitters that are not being used for the message delivery, excepting those that will or may interfere with the delivery, may be concurrently used to deliver or transmit other messages. However this improved reuse requires very current knowledge of messaging unit location so the proper transmitter(s) may be used. Less accurate knowledge of the units location will result in dramatically lower reuse due to poor transmitter selection and multiple message repeats in systems, such as two-way paging where units are expected to acknowledge messages. Accurate location knowledge for mobile users often comes at a price. For example, inbound channel capacity devoted to receiving location information from the selective messaging units can be strained, the processing power devoted to analyzing and updating this information may be become prohibitive, and the battery capacity of the messaging units devoted to updating location information may be undesirable. Additionally poorer coverage may result in the absence of simulcast operation.
Clearly a need exists for apparatus and methods of providing coverage in a selective messaging system that provides improved or enhanced reuse capability without unduly sacrificing other operational attributes.